compressor-less dehumidifier, puts off little heat

I have two 4x4 rooms for growing. In the past ,this time of the year my humidity has always been 50%. This year it is staying at 70-85% in the first room and 60-80% in the second room. The rooms are vented 20 hours a day and have fans going all day during the photo period and 30 min. intervals during the night.

Heat is a big problem for me. Even with my AC going 14 hours a day my temps stay 75-85. The fan running 20 hours a day pulls through my two vented hoods. I need a dehumidifier, but I can't deal with the heat it would put out. I am looking at compressor-less dehumidifiers. I know they are very weak, but will it work in a 4x4x8 room?

They have mixed reviews and none were for grow rooms. The unit is $55 shipped to my house and I should be able to return it to my local wall mart if it does not work. Does anyone have experience with on of these?

Search Sunpentown Mini Dehumidifier SD-350 at wallmart.com to see an example of what I am looking at.

bump for the day crew.

well could try whats called damp-rid helps drop humidity with no electric or motors

you will need a lot of damprid to keep the moisture in check. I am interested as well if you go that way please post your results

dont know bout that. my room is 5x7x7 and i use one little bucket of damp rid and it helped a lot. but on the other hand that ac should be helping with your humidity problem. Maybe check online for larger ac

joe dollar said:

dont know bout that. my room is 5x7x7 and i use one little bucket of damp rid and it helped a lot. but on the other hand that ac should be helping with your humidity problem. Maybe check online for larger ac

Click to expand...

How long does that small bucket of damp rid last in your 5x7x7?

I have found a different unit that is getting better reviews than the first I posted. It is the Eva-Dry EDV-2200 and in one review, the person said it was for a grow room and that it worked good.

• Model: EDV-2200
• Product Type: Portable mid-size room dehumidifier
• Product Dimensions: 7"L x "8.5"W x 14"H
• Product Weight: 6.7 lbs.
• Product Color: White
• Effectiveness: 2,200 cubic ft.; approxinmately 20.5 oz./day @ 86 degrees Fahrenheit and 80% RH
• Cooling: Thermo-electric Peltier module
• Power Adapter: 12V DC 6AMP
• Power Consumption: 72W
• Removable Water Tank: 2 liter capacity
• Water Level Detector: Automatic switch to indicate tank is full
• Uses little energy for your environmental consciousness
• Small enough to be placed out of sight and out of mind
• Features an auto shut off function when it reaches moisture capacity
• Uses Peltier technology to deliver you great dehumidifying
• Economically priced for your convenience and comfort

I'm having about the same problems you are, Gold, and I tried one of these Eva-Drys. Let it run for over twelve hours and while it did remove some moisture, it didn't bring down my RH one bit. Not one single percentage point. I really don't think it does much more than one of the Damp-Rids. I returned it. Not even close to being worth the $50 it cost me.

What kind of exhaust fan are you using? You might be better off putting your attention there. That's what I am doing.

TheDudeNextDoor said:

I'm having about the same problems you are, Gold, and I tried one of these Eva-Drys. Let it run for over twelve hours and while it did remove some moisture, it didn't bring down my RH one bit. Not one single percentage point. I really don't think it does much more than one of the Damp-Rids. I returned it. Not even close to being worth the $50 it cost me.

What kind of exhaust fan are you using? You might be better off putting your attention there. That's what I am doing.

Click to expand...

Damn, I just placed an order for the 2200 unit before seeing your reply. You said $50, so I am guessing you had the 1100? The 2200 uses almost four times the power. How big is your room and what was the RH if you don't mind me asking?

My exhaust fan is a 640 cfm unit on a speed controller that is turned down very low, but enough to keep my 600 and 400 cool. They draw air from my grow rooms, so if I turn the fan up it will suck out the cold AC air and not let the room cool down. I would have to guess with the speed controller it is running around 75-150 cfm and I believe that to be sufficient for the two 4x4 rooms.

Yes, it was the 1100. You might have better results with the 2200, but temper your expectations. To give you an idea of my experience, the 1100 pulled about the same moisture in 12 hours as a large Damp-Rid pulls in 24 hours. So perhaps you can double that with the 2200. Like I said, though, I got zero RH drop. On the other hand, it's got to help with possibility of bud rot, so I don't think it's a waste of money. I just figured for $50, I expected better. It was more cost effective for me to use a large Damp-Rid. Just make sure you have plenty of air movement in your boxes, especially your flower box. My research indicates that you can actually get by with high RH if you have good air movement.

My box is 5'L x 3'W x 4.5' H. I was averaging temps of 84-86 with RH of low 40s during veg. When I started flowering, though, my RHs jumped to upwards of 60s or higher. I've made some modifications to have better air exhaust (still working on that) and have brought my average numbers down to 77-80 temps / 45-50 RH. I also have a large Damp-Rid in there, but that's more for further protection against bud rot than any hope of lowering RH. I also have one 10" fan oscillating through the canopy and one box fan titled to blow up through the body of the plants. I keep my plants fluttering at all times.

I'm not sure what your setup is, but this is what I do to keep from exhausting all my AC. Bear in mind that my enclosed box is in a larger room, and the room is dedicated to the grow; in other words, I don't use the room for any other purpose. I have my exhaust pulling from a vented hood within the box and exhausting back into my room. This keeps my air constantly circulating rather than exhausting outside and overtaxing my AC. Like I said, that may not be an option for you if you use your room for other purposes, but it works great if you have a dedicated grow room. If you can do this, it would allow you to up your fan speed to get better air movement in the box, which I think is your best bet for a temp/RH cure.

When you get that 2200 and have a chance to try it out, would you come back here and post your results? I'd still like to have better control over my RH without the heat of a compressor-driven dehumidifier. If the thing is worth the money, I would be willing to drop the change.

Once I get the unit and give it some time to work, I will post an update for sure. It will be interesting to see what happens.

I'd love to read how it works out for you

UPDATE

I got the unit yesterday and fired it up. So far it has been about 20 hours of use at 4 hours on and 2 hours off. Both of my 4x4 rooms have always had identical humidity, as they are back to back in the same room. Today the humidity in the room w/o the unit is at 80% right now and the room with the unit is 67%. So it lowered a 4x4x8 room 13% in a 20 hour period.
I might have to run 2 units in each room to get the RH where I want it. 4 units at $85 each is about the same price as a normal big dehumidifier that would work a lot better, but the 2200 does do what I was looking for. It lowers the humidity w/o creating any heat.

That's encouraging. Thanks for the update, Goldowitz!

UPDATE #2

The unit works better the higher the RH of the area is. My first report was when the area was at 80% RH, the unit lowered it 13%.
Now that the area is 72% RH the unit lowers the room to 64%, or an 8% difference.

Great thread. My RH plays around 60-80% (temps 80-90) and I'm looking for solutions as well..

I wonder if adding another unit will reduce it by another 8%.
Probably not coz based on your post, it's less effective when the RH is lower.

Does that mean that we can not achieve 40-50% humidity with these?

This is an old post but how did the Eva 2200 work out?